In the story of human origins, the first primates were small, unremarkable tree dwellers in a world full of diverse mammals of all sizes. Over several million years, primates branched out into the groups known as monkeys and apes. Their larger brains led to new variety in mammal adaptation that led to the development of social groups and sophisticated survival strategies. From the apes evolved a new, highly intelligent kind of primate, the hominins, ancestors of the human species. The richly illustrated ""Primates and Human Ancestors"" tells the story of 50 million years of primate evolution during the Pliocene epoch, from their origins in Africa to their spread to the New World and origin of the human species.